1. Field of the Invention
This invention relates in general to radio frequency (RF) communication systems, and in particular, to a method and apparatus for fraud control in cellular mobile radiotelephone (CMR) and personal communications services (PCS) systems.
2. Description of Related Art
Cellular telephones combine the mobility of the radio link and the world-wide land telephone network to provide a communication link to any other telephone in the world. However, as cellular phones have become more prevalent throughout the country, fraud has become a major problem. Cellular fraud robs service providers of hundreds of millions of dollars every year. Like all crimes, there are several varieties of cellular fraud, including "cloning."
Cloning fraud, which occurs when a legitimate subscriber's MIN/ESN combination is used for illegal purposes, is among the most sophisticated and difficult forms of fraud to prevent. Often, the pirate will use simple electronic devices to "capture" the legitimate MIN/ESN combination during its transmission by radio frequency (RF). In these cases, the legitimate subscriber often does not know fraud is being committed with his or her MIN/ESN combination until they receive the bill. This is currently the most popular method of gaining illegal access to a cellular system, because the legitimacy of the stolen MIN/ESN combinations makes cloning difficult to catch.
There are certain steps that can be taken to prevent cloning fraud. In some instances, carriers block calls to certain destinations, or impose "brownouts" on calls using specified MIN codes, particularly on international calls, that have been previously abused. Although drastic, this method currently is often the only way to stop cloning fraud.
The eventual release of digital cellular phones into the mass market will provide another avenue for fraud. Digital phones will also be susceptible to new and improved criminal techniques for stealing MIN/ESN combinations. Thus, carriers are forced to seek other methods of detecting and preventing fraudulent calls.
Several companies, including Electronic Data Systems (EDS) and Subscriber Computing, Inc. (SCI) have developed anti-cloning products that analyze calling patterns using call records. For example, EDS' PCC Cloning Detection System and SCI's Fraud Watch System are designed to be interfaced with cellular switches, so that call information can be collected after the calls have been completed. These systems can be used to identify calling patterns in the collected information that indicate fraudulent usage.
These systems typically allow operators to specify certain criteria to identify fraud. These criteria may include number of calls per hour, call durations, number of minutes used by a specific phone within an hour, number of international or toll calls per hour, and calls to specific countries or NPA/NXXX codes. Operators can also identify fraudulent usage by the specific number dialed for those numbers that have been previously identified as a number called by fraudulent callers. The call records of cellular phones meeting any number of criteria can be viewed online or printed.
Although they cannot prevent cloning fraud, such systems provide carriers with a method of identifying cloning fraud, so that losses can be tabulated. Unfortunately, current methods can only detect or monitor fraud after the caller hangs up, and provide no way to stop fraud. Thus, there is a need in the art for techniques that enhance the use of analyzed call patterns to deny pirates the use of cellular telephone systems.